Less Wrong Rationality and Mainstream Philosophy

Part of the sequence: Rationality and Philosophy

Despite Yudkowsky’s distaste for mainstream philosophy, Less Wrong is largely a philosophy blog. Major topics include epistemology, philosophy of language, free will, metaphysics, metaethics, normative ethics, machine ethics, axiology, philosophy of mind, and more.

Moreover, standard Less Wrong positions on philosophical matters have been standard positions in a movement within mainstream philosophy for half a century. That movement is sometimes called “Quinean naturalism” after Harvard’s W.V. Quine, who articulated the Less Wrong approach to philosophy in the 1960s. Quine was one of the most influential philosophers of the last 200 years, so I’m not talking about an obscure movement in philosophy.

Let us survey the connections. Quine thought that philosophy was continuous with science—and where it wasn’t, it was bad philosophy. He embraced empiricism and reductionism. He rejected the notion of libertarian free will. He regarded postmodernism as sophistry. Like Wittgenstein and Yudkowsky, Quine didn’t try to straightforwardly solve traditional Big Questions as much as he either dissolved those questions or reframed them such that they could be solved. He dismissed endless semantic arguments about the meaning of vague terms like knowledge. He rejected a priori knowledge. He rejected the notion of privileged philosophical insight: knowledge comes from ordinary knowledge, as best refined by science. Eliezer once said that philosophy should be about cognitive science, and Quine would agree. Quine famously wrote:

The stimulation of his sensory receptors is all the evidence anybody has had to go on, ultimately, in arriving at his picture of the world. Why not just see how this construction really proceeds? Why not settle for psychology?

But isn’t this using science to justify science? Isn’t that circular? Not quite, say Quine and Yudkowsky. It is merely “reflecting on your mind’s degree of trustworthiness, using your current mind as opposed to something else.” Luckily, the brain is the lens that sees its flaws. And thus, says Quine:

Epistemology, or something like it, simply falls into place as a chapter of psychology and hence of natural science.

Yudkowsky once wrote, “If there’s any centralized repository of reductionist-grade naturalistic cognitive philosophy, I’ve never heard mention of it.”

When I read that I thought: What? That’s Quinean naturalism! That’s Kornblith and Stich and Bickle and the Churchlands and Thagard and Metzinger and Northoff! There are hundreds of philosophers who do that!

Non-Quinean philosophy

But I should also mention that LW philosophy /​ Quinean naturalism is not the largest strain of mainstream philosophy. Most philosophy is still done in relative ignorance (or ignoring) of cognitive science. Consider the preface to Rethinking Intuition:

Perhaps more than any other intellectual discipline, philosophical inquiry is driven by intuitive judgments, that is, by what “we would say” or by what seems true to the inquirer. For most of philosophical theorizing and debate, intuitions serve as something like a source of evidence that can be used to defend or attack particular philosophical positions.

One clear example of this is a traditional philosophical enterprise commonly known as conceptual analysis. Anyone familiar with Plato’s dialogues knows how this type of inquiry is conducted. We see Socrates encounter someone who claims to have figured out the true essence of some abstract notion… the person puts forward a definition or analysis of the notion in the form of necessary and sufficient conditions that are thought to capture all and only instances of the concept in question. Socrates then refutes his interlocutor’s definition of the concept by pointing out various counterexamples...

For example, in Book I of the Republic, when Cephalus defines justice in a way that requires the returning of property and total honesty, Socrates responds by pointing out that it would be unjust to return weapons to a person who had gone mad or to tell the whole truth to such a person. What is the status of these claims that certain behaviors would be unjust in the circumstances described? Socrates does not argue for them in any way. They seem to be no more than spontaneous judgments representing “common sense” or “what we would say.” So it would seem that the proposed analysis is rejected because it fails to capture our intuitive judgments about the nature of justice.

After a proposed analysis or definition is overturned by an intuitive counterexample, the idea is to revise or replace the analysis with one that is not subject to the counterexample. Counterexamples to the new analysis are sought, the analysis revised if any counterexamples are found, and so on...

Refutations by intuitive counterexamples figure as prominently in today’s philosophical journals as they did in Plato’s dialogues...

...philosophers have continued to rely heavily upon intuitive judgments in pretty much the way they always have. And they continue to use them in the absence of any well articulated, generally accepted account of intuitive judgment—in particular, an account that establishes their epistemic credentials.

However, what appear to be serious new challenges to the way intuitions are employed have recently emerged from an unexpected quarter—empirical research in cognitive psychology.

With respect to the tradition of seeking definitions or conceptual analyses that are immune to counterexample, the challenge is based on the work of psychologists studying the nature of concepts and categorization of judgments. (See, e.g., Rosch 1978; Rosch and Mervis 1975; Rips 1975; Smith and Medin 1981). Psychologists working in this area have been pushed to abandon the view that we represent concepts with simple sets of necessary and sufficient conditions. The data seem to show that, except for some mathematical and geometrical concepts, it is not possible to use simple sets of conditions to capture the intuitive judgments people make regarding what falls under a given concept...

With regard to the use of intuitive judgments exemplified by reflective equilibrium, the challenge from cognitive psychology stems primarily from studies of inference strategies and belief revision. (See, e.g., Nisbett and Ross 1980; Kahneman, Slovic, and Tversky 1982.) Numerous studies of the patterns of inductive inference people use and judge to be intuitively plausible have revealed that people are prone to commit various fallacies. Moreover, they continue to find these fallacious patterns of reasoning to be intuitively acceptable upon reflection… Similarly, studies of the “intuitive” heuristics ordinary people accept reveal various gross departures from empirically correct principles...

There is a growing consensus among philosophers that there is a serious and fundamental problem here that needs to be addressed. In fact, we do not think it is an overstatement to say that Western analytic philosophy is, in many respects, undergoing a crisis where there is considerable urgency and anxiety regarding the status of intuitive analysis.


So Less Wrong-style philosophy is part of a movement within mainstream philosophy to massively reform philosophy in light of recent cognitive science—a movement that has been active for at least two decades. Moreover, Less Wrong-style philosophy has its roots in Quinean naturalism from fifty years ago.

And I haven’t even covered all the work in formal epistemology toward (1) mathematically formalizing concepts related to induction, belief, choice, and action, and (2) arguing about the foundations of probability, statistics, game theory, decision theory, and algorithmic learning theory.

So: Rationalists need not dismiss or avoid philosophy.

Update: To be clear, though, I don’t recommend reading Quine. Most people should not spend their time reading even Quinean philosophy; learning statistics and AI and cognitive science will be far more useful. All I’m saying is that mainstream philosophy, especially Quinean philosophy, does make some useful contributions. I’ve listed more than 20 of mainstream philosophy’s useful contributions here, including several instances of classic LW dissolution-to-algorithm.

But maybe it’s a testament to the epistemic utility of Less Wrong-ian rationality training and thinking like an AI researcher that Less Wrong got so many things right without much interaction with Quinean naturalism. As Daniel Dennett (2006) said, “AI makes philosophy honest.”

Next post: Philosophy: A Diseased Discipline


Dennett (2006). Computers as Prostheses for the Imagination. Talk presented at the International Computers and Philosophy Conference, Laval, France, May 3, 2006.

Kahneman, Slovic, & Tversky (1982). Judgment Under Uncertainty: Heuristics and Biases. Cambridge University Press.

Nisbett and Ross (1980). Human Inference: Strategies and Shortcomings of Social Judgment. Prentice-Hall.

Rips (1975). Inductive judgments about natural categories. Journal of Verbal Learning and Behavior, 12: 1-20.

Rosch (1978). Principles of categorization. In Rosch & Lloyd (eds.), Cognition and Categorization (pp. 27-48). Lawrence Erlbaum Associates.

Rosch & Mervis (1975). Family resemblances: studies in the internal structure of categories. Cognitive Psychology, 8: 382-439.

Smith & Medin (1981). Concepts and Categories. MIT Press.